Two temperature evaporator for inert gas type absorption refrigerators



Sept- 17, 1946 c. T. AsHBY TWO TEMPERATURE EVAPORATOR FOR INERT GAS TYPE ABSORPTION REFRIGERATORS Filed may 15, 1941 2 sheets-sheet 2 ATTORNEY.

Patented S'ept. 17, 1946 TWO TEMPERATURE EVAPORATOR FORl IN ERT GAS TYPE ABSORPTION REFRIG- ERATORS Carl T. Ashby, Evansville, Ind., assigner to Servei,

Inc., New York, N. Y., a corporation of Dela- Ware Application May 15, 1941, Serial N0. 393,558`

1 18 Claims. 1 s

My invention relates to refrigeration and more particularly to refrigeration produced by evaporation of liquid in the presence of auxiliary inert gas. A Y

It is an object of the invention to produce refrigeration simultaneously at different temperatures and maintain a distinct differential between such temperatures.

It is another object to providea coil-type evaporator for pressure equalized refrigeration apparatus having distinct temperature zones.

It is another object to provide an evaporator for pressure equalized absorption refrigeration apparatus having high and low temperature zones with increased cooling capacity of -the higher temperature zone.

The above, together with other objects and advantages, are more f ully set forth and explained in the following description in `connection with the accompanying drawings forming part of this specification and of which:

Fig. lshows more or less diagrammatically a refrigeration apparatus embodying the invention;

Figffshows schematically a refrigerator provided with a cooling element embodying the invention;

Fig. 3 is an enlarged View, partly broken away, of the coolingv element shown in Fig. 2;

Fig. 4 is a sectional view taken on line 4--4 in Fig. 3; and

Fig. 5 is a sectional view taken on line 5-5 in Fig. 4.

Referring to Fig. 1, the refrigeration system includes a generator I0 heated by suitable means such as a gas burner II. The generator I 0 is connected with an absorber I2 by conduits in- A coil type] evaporator 25 is located in a refrigerator storage compartment 26. Evaporator 25 comprises a coil section 21 forming one part and a coil section 28 forming other parts.` A conduit 29 'is connected from the condenser trap 22 to the upper part of coil section 28. Conduit 30 is connected from condenser trap 23 to an intermediate part of coil section 28. A conduit 3l is connected from condenser trap 24l to a bottom part of coil section 28. A downward looped conduit 32 is connected from the lower'end of said upper part of coil section 28v to the upper end of coil section 21. A similar conduit 33 is connected from saidintermediate part of coil section 28 to an intermediate turn in coil section 21. Another similar conduit 34 is connected from the lower end of Vsaid bottom part of coil section 28 to a lower turn of coil section 21.` A drain conduit35is connected from the lower enclY of coil section 21`to the inner passage of a. gas heat exchanger 36.

The upper end of coil section 21 is connected to the upper end of coil section 28 and the .latter is locatedas a whole at al slightly higher elevation than that of coil section 21. The lower end of evaporator coil section 21 is connected by a conduit 31, outer passage of gas vheat-exchanger 3B, and a conduit 38 to the upper part of absorber I2. The lower end of evaporator section 28 is connected by a conduit 39, inner passage of gas heat exchanger 36, and a conduit to the lower cluding a liquid heat exchanger I3 for circulaI tion of absorption liquid through and between the generator and absorber. The generator I0 is provided with a vapor liquid lift I4 tocarry out this liquid circulation in known manner. The absorber I2 is shown provided with a coil I2a for circulation of a cooling fluid. Fins could be used for direct air cooling of the absorber, as known.`

The generator I0 is connected by a conduit I5', a rectifier I6, and a conduit I1 to the upper end of an air-cooled condenser I8. The condenser I8 comprises an upper section I9, an intermediate section 20, and a lower section 2|. A liquid trap 22 is connected between the two upper condenser sections I9 and 20, a liquid trap 23 is connected between the two lower condenser sections 2U and 2l. A liquid trap 24 is connected to the bottom condenser section 2|. A

part of evaporator I2.

The top of condenser trap 24 is connected by a conduit 4I .to one end of a vessel 42. The other end of vessel 42 is connected by a conduit 43 to conduit39 in the evaporatorabsorber gas circuit.

The above described system is evacuated and charged with refrigerant uid, an absorbent therefor, and an inert auxiliary iiuid. Ammonia,

i water, and hydrogen `may be used.` The ammonia and water are flowed into the system as a solution, and the hydrogen'r is flowed into the system under a pressure such that the total pressure in the-system will be the condensing temperature of ammonia at a fairly high room temperature. l Y

In operation, burner I I is lighted to heat generator Ill. Ammonia vapor is expelled from solution'` by heating in the generator. Vapor formed in the generator and which rises through conduit I4 causes upward flow of liquid through thisconduit byknown vapor lift action so that liquid flows by gravity through the rest of the .generator-absorber liquid circuit. All the genvapor in condenser section 2e flows through trap l 23 and conduit 39 into the intermediate part Vof coil 28. Liquid formed by condensation 'of vapor in lower condenser section 2`I flows throughltrap 2d and conduit 3I into the bottom part of coil section 28.

in refrigerator 26, either by manual adjustment of burner I I or by thermostatic control of burner- In operating thesystem so ,that a substantially constant temperature is maintained 4 evaporator coil section 28 is located outside of and around the coil section 21. The coil section 23 is arranged in thermal conductive relation with an outer sheet metal casing 41 provided with heat transfer fins 48. The coil section 28 and itscasing shields the inner .casing 4G and the low temperature coil section 21 from contact with. air in the refrigerator.

Between the inner evaporator casing 46 and outer casing 41 is a dead air space 'which thermally insulates the low temperature or freezing section.

Since Asubstantially none of the air cooling load is imposed Aupon' the low temperature evaporator l coil section 21, only a small amount of ammonia load-thereon is small.

l I responsive to a temperature condition affected" by the evaporator as known, vapor will 'be-con.

densed only in the upper sections of the condenser under low vloadconditions so that liquid will-dow .from the condenser onlyinto the upper part or parts4 of evaporator coil section 28, yand, liquid willbe supplied from the condenser to all par-ts of evaporatorl coil section A28 onlyV under increased load conditions. Dams 44 are located in'evaporator coil section 28 so that, for instance, liquid 'supplied to the upper part of coil section .-28 flows only through this section` and thence through conduit 32 to the coil section 21. However, any liquid which enters `evaporator' coil seetion 1j Will ow downward in this coil section from its point of entrance to such point as it may be used up by evaporation.

Wherever liquid is present in the evaporator coil, it evaporatesand diffuses into the hydrogen, In 'starting operation, `liquid Yfirst enters coil `secltion-2B sov that the addition .of heavy ammonia .vapor to gasinthis coil causes gas irculationt'o start downward in coil section 2&3 and gas `circu-` latio-n continues in the direction ofthe arrows in Fig. l. The flow is fromvrthe lowerv endv ofrcoil section 28 to the absorber I2. Y t l f l 4Ammonia vaporis absorbed into absorption liquid in absorber I2'. rl'he hydrogen fromwhich ammonia has been absorbed, that is weakv gas, returns from theY absorber through the `gas heat exchanger 36 to the lower end of evaporator coil section 21. v Gas flow is upward ,throughv coil section 21 and downward through coil section r,28. Ammonia evaporates at a temperature dependent upon the partial pressure of ammonia vapor in thevpresence of the evaporating liquid. Since weak gas ows iirst in coil section 21, the partial pressure of ammonia vapor in this coil section is less than the partial pressure of ammonia vapor in coil section 28. Therefore, the temperature of coil section 21 is lower than the temperature of coil section 28. t

The evaporator coils shown diagrammatically in Fig. l are formed into a usable cooling element which is shown located in a household refriger ator in Fig. 2 and illustrated in detail sections Figs; 3, 4 and-5. Referring to Fig.y 2, andvprincipally to, Figs. 3, fl, and 5., the evaporator 25 located in the storage compartment 2I`o'f arekf rigerator' is formed to provide a low temperaturezonefor freezing wateror the like, and a higher temperature Zone for Vcooling of air in the refrigerator. The evaporator coil section 21 is arranged in good thermal conductive'relation with an Vinner casing 46, ,Casing 46 forms a plu-` rality of compartments to receive ice freezing trays or the like. Asshown, coil section`2'1`isA embedded in an aluminum casting 45.' The evaporates in this coil section when the freezing Under such conditions the gas entering the higher temperature coil section'28jwill contain a relatively small quantity of ammonia vapor so that, under such conditions, theI te na-perature4 of the` part of this coil section which isi connected to the ,low temperature sectionv 21 would be cold, thus lowering the' humid'-y ity of air in the refrigerator`V compartment. However, by introducing hot ammonia liquid fromthecndenser through conduits 29, 3l), and 3I Yatpoints distributed along the length of coil section 28, the temperature of this coil is mainy tained higher so that better humidity of air in the refrigerator compartmentis obtained even with smallfload on the freezing -coil 21. 'j

Referring again to lFg. 1, when uncondensed ammonia vapor `issues from the lower Vend of condenser I3, as upon increase in temperature of the ,cooling ainthe vapor flows through conduit ,s 4l into Vessel 42 andl displaces'rhydrogen from this reserve vessel through conduit 43 vinto the evaporator-absorber gas circuitso that the `total pressure in the system rises to the necessary condensing pressureV of vammonia at the increased temperature and l.refrigeration continues at this increased pressure. Ammonia vapor which' Ycondenses in Yvessel 4I2 drains Ythrough conduit 4I, trap `2ll,and conduit 3l into the lower part lof evaporator coil 28. 'Various'. changes andrmodcations may be made within the scope of the invention asset forth in the following claims. I

What is claimed is: Y y l. A refrigeration system having a plurality of parts in which evaporation of refrigerantliquid occurs to produce refrigeration, means .for flowing inert gas through said parts in series, meansproviding thermal insulation between a lfirst of said par-ts on one `hand and others of Said parts on the other, and mean-s for simultaneously .introducing liquid refrigerant .individually into said otherparts, said rst partbeing 'connected Vand arranged to receive liquid from saidother parts. 2.l A refrigeration system having-a pluralityof parts in which evaporation of refrigerantyliquid occursto produce refrigeration, means for'flow ing inert `gas through said parts in seriespmeans proyiding'thermal insulation between a'lrstof said'parts on one "handI and othersof saidj parts on thegother, means for simultaneously conducting liquid refrigerant individually to said other parts, and means for simultaneously vconducting liquid refrigerant individually from said other partsrto fsa-id first part'. l '3, A refrigeration vsystem vhaving a plurality of partsin vwhich evaporation of refrigerant 'liquid occurs to produce refrigeration, means for flow; ing inertgasA throughsaid parts`,`.means.for smul taneou-sly conducting liquid-refrigerant individually to some of said parts, and means for simultaneously conductingliquid individually from said some parts toanother'of said parts.v

4. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration, means providing thermal insulation between a first of said parts on one hand and others of said parts on the other, a refrigerant fluid liqueiier, means for conducting liquefied refrigerant fluid from said liqueer individually and simultaneously to said other parts, means for conducting liquid from said other parts to said first part, and means for flowing inert gas through said first part and then through said other parts.

5. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration, a refrigerant fluid liqueer, means for simultaneously conducting liquefied. refrigerant fluid from said liqueer individually to some of said parts, means for simultaneously conducting liquid individually from said some parts to another of said parts, and means for flowing inert gas through said parts.

6. In a refrigerator having a food storage compartment, a refrigeration system having a plurality of parts inwhich evaporation of refrigerant liquid occurs to produce refrigeration, a freezing chamber in heat transfer relation with a rst of said parts, means providing thermal insulation between said first part and said chamber on one hand and others of said parts on the other, said other parts being arranged to cool air in said refrigerator storage compartment, means for simultaneously conducting liquid refrigerant individually to said other parts, means to conduct liquid from said other parts to said rst part, and means to flow inert gas through said first part and then through said other parts.

7. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration, a first of said parts being en folded by and insulated from others of said parts, means for conducting liquid refrigerant individually to said other parts, means to conduct liquid from said other parts to said first part, and means to flow inert gas through said first part countercurrent to flow of liquid therein and then through said other parts concurrent to ow of liquid therein.

8. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration, some of said parts encompassing another of said parts in spaced relation thereto, means providing a dead air space enveloping said other part, means for conducting liquid refrigerant individually to said some parts, means for conducting liquid from said 'some parts to said other part, and means for iioW- ing inert gas through said other part and then through said some parts.

9. A refrigerator including a cabinet having a storage compartment, a cooling element in said compartment having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration, one of said parts being encompassed by others of lsaid parts and insulated therefrom, a freezing chamber associated with said one part, said other parts being provided with means for cooling of air in said compartment, means to conduct liquid refrigerant individually to said other parts, means to conduct liquid from said other parts to said one part, and means to iloW inert gas through said one part and then through said other parts.

10. A refrigerator cooling element including a 6 freezing chamber, a pipe coil arranged for cooling said chamber, a second pipe coil encompassing said first coil'and cooling chamber in spaced relation thereto, a casing thermally associated with said second coil providing exteriorly an `air coolingsurface and interiorly a dead airspace, means for conducting liquid refrigerant individually to different partsmof said second coilg'm'eans for conducting `liquid from said-.second coil to said first coil, and-'means'for flowing inertv gas i through said first coil and then through said second coil.

11. A refrigerator cooling element including a freezing chamber, a first pipe coil thermally associated with said chamber, a second pipe coil located about said first coil and freezing chamber and insulated therefrom, said second coil being provided with heat transfer surface for cooling air, means for conducting liquid refrigerant individually to different parts of said second coil, means for conducting liquid from said second coil to said rst coil, and means for flowing inert gas through said first coil and then through said second coil.

12. A refrigeration system having two sections in which evaporation of refrigerant liquid occurs to produce refrigeration, one of said sections shielding the other of said sections from ambient air, means for flowing inert gas through said sections, means for conducting liquid refrigerant individually to different parts of said one section,

and means for conducting liquid refrigerant; individually from said parts to said other section.

13. A refrigeration system having a plurality of thermally separated sections in which evaporation of refrigerant liquid occurs to produce refrigeration, means for flowing inert gas through said sections, means to simultaneously conduct liquid refrigerant individually to different parts of one of said sections, and means to simultaneously conduct liquid individually from said parts to another of said sections.

14. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration at distinctly different temperatures, structure providing thermal insulation between a first of said parts on one hand and others of said parts on the other, structure for introducing warm liquid refrigerant into said other parts, said first part being connected and arranged to receive liquid from said other parts, and means for flowing inert gas through said first part countercurrent to flow of liquid therein and then through said other parts concurrent to flow of liquid therein.

` 15. A refrigeration system having a plurality of parts in which evaporation of refrigerant liquid occurs to produce refrigeration at distinctly different temperatures, structure for conducting warm liquid refrigerant individually to some of said parts, structure for conducting liquid individually from said some parts to another of said parts, and means for flowing inert gas rst through said another part and then concurrent to flow of liquid in said some parts.

16. A refrigeration system having a plurality of thermally separated sections in which evaporation of refrigerant liquid occurs to produce refrigeration at distinctly different temperatures, structure to conduct warm liquid refrigerant individually to different parts of one of said sections, structure to conduct liquid individually from said parts to another of said sections, and means for flowing inert gas rst through said another section and then concurrent to flow of liquid in said different parts of said onesection.

17'. A refrigeration system having a plurality 0f thermally separated sections in whichevaporation'of refrigerant liquid occurs to produce refrigeration at distinctly different temperatures, structure to conduct warm liquid refrigerant to one of said sections and thence to another of Vsaid sections, and means for owing inert gas rst through saidanother section and then concurrentto flow of liquid in said one section.

1 18. A refrigeration system having a. cooling element including a rst pipe coil and a second pipe coil, a refrigerant uid liqueer, means .for simultaneously conducting liquid refrigerant from said liqueer individually to diierent parts of said second coil, and means for simultaneously conducting liquid individually from said parts to said Yrst; coil.

CARL T. ASHBY. 

